8128( 4) - 03/30/00 11:46 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8128 Version: 4 Check-in Date: 30-Mar-2000 11:45:08 1.Proposal Title: Stalking FLIERs in Planetary Nebualae: a STIS Study ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Mario Perinotto Universita di Firenze CoI: Prof. Bruce Balick University of Washington N CoI: Dr. Romano Corradi Instituto de Astrofisica de Canarias N CoI: Dr. Patrizio Patriarchi Consiglio Nazionale delle Ricerche N ------------------------------------------------------------------------------------ 5. Abstract FLIERs are enigmatic pairs of small, low-ionization knots located on opposite sides of the central star of many PNe. Their symmetric locations, equal, opposite and supersonic Doppler shifts (Mach 3-5), and highly enriched N/O ratios (~3- 7) suggest that they are peculiar spitballs ejected recently from the stellar interior. As expected, WFPC2 studies spatially resolved the FLIERs and revealed the presence of bow shocks --- but unexpectedly, the tails point precisely in the wrong direction. Bow shock models also predict the highest ionization at the head of the shock. FLIERS always exhibit the reverse ionization gradient. What are FLIERs? Where do they come from? What clues can we uncover about their state and history? How do they relate to their surroundings? How do they differ from other knots which aren't FLIERs? Our goal is to use STIS at high dispersion to study the hydrodynamic state (e.g. velocity field, shocks, etc.) and low dispersion to study the physical and che mi cal state of FLIERs and nonFLIERs alike. The hydrodynamic results can be compared directly to predictions of calculations of Oort-Spitzer "rockets", dense bullets, and the ablation flows of knots in a strong mechanical wind (``mass-loaded flows''). The photometric data will be used to understand the density, temperature, and abundances and their distributions within FLIERs. ------------------------------------------------------------------------------------ 8128( 4) - 03/30/00 11:46 - [ 2] Observations Description ------------------------ The observations will be made in two positions in NGC 7662, A and B, with the STIS G750M/6591, G750M/5734, and G430L gratings. Slit Placements: POS 1 (P.A. 13 degrees) will cover the bright SW FLIER and the central star of NGC 7662 about 15" from the FLIER, through the main nebula shells. POS 2 (P.A. 52 degrees) will include the NON-FLIER N condensation lying at a similar distance from the central star at the edge of the nebula. The central star will enter the slit in both positios; however, its light will not affect the quality of the spectra. Kinematics: We shall obtain kinematics along a 0.1" slit in the HAlpha and N II lines in the FLIER, nonFLIER, and the surrounding nebulosity (grating G750M, tilt=6591). With this slit width we should be able to measure line wavelengths to an accuracy corresponding to 10\ absolute wavelengths are not important, changes in Doppler shift along the slit are the key to determining the kinematic patterns that can be compared to models. O ne orbit per slit position is requested since the surface brightnesses of the lines are bright. Emission Line Imaging and Photometry: Exposures will be made through a 0.5x52" slit for all of the target regions in various diagnostic lines. The wavelengths of the most important lines are 3727, 3869, 4340, 4364, 4861, 4959, 5007, 5755, 5876, 6300, 6548/83, 6563, 6716, 6731. Some of these line are isolated in the spectrum, so for them G430L exposures will suffice. However, other lines overlap with comparable or brighter lines and, so, can be isolated only with the G430M or G750M gratings. Even with the medium gratings Doppler shifts will be small and ignorable through the wide slits. We also have good set of narrowband PC for all of the knots and shells NGC7662 from GO 6117- Balick. However, the nonoverlapping images of N II 6583 & HAlpha, and S II 6717 & S II 6731 are mandatory. Hence we request time for extra G750M exposures at grating tilts 6591 and 5734. (The 5734 tilt will be e xplained below). This procedure provides strip image ratios of N II 5755/6583, S II 6717/6731, N II 6583/HAlpha, S II 6725/HAlpha, and He I 5876/HAlpha which are unaffected by Doppler shifts. We request the G750M strips of these lines to minimize the effects of Doppler smearing in order to form high-quality N II 5755/6583 and HeI 5876/HAlpha strip ratios. Most of the values of the ionic abundances derived throughout the strip images are highly dependent on the accuracy of the N II 5755/6583 ratio. Given the spectral nature of the nebula and the knots certain compromises are possible in order to save time without compromising any key scientific goals. For example, the FLIERs are very faint in O III 5007, so observations that separate O III 4363 from HGamma 4340 are not crucial. The G430L/0.5" observations can be made in two orbits per each slit position since the nonoverlapping lines of particular interest are sufficiently bright. If necessary we can blockaverage the data to i mprove the S/N. For each slit position we need one orbit for G750M/0.5" (tilt=6581 A) and four orbits for G750M/0.5' (tilt=5734 A) since the N II 5755 temperature diagnotic line is particularly weak. The exposure times have been carefully evaluated from counts measured in the specific knots directly from various uncalibrated narrowband PC images (GO 6117). The STIS S/N in per orbit integration has been estimated from the PC images after correcting for the ratio of system throughputs, readout gains, and slightly larger STIS pixel sizes, and then correcting the STIS count rates for the expected spectral dispersion of the line by the grating. For lines such as N II 6583, HeI 5876, and S II a S/N of 30, 20, 10, respectively, is expected. The worst case is expected to be N II 5755 for which four orbits of integration yield a S/N of about 3. Finally, since we have photometrically calibrated PC images in the lines of O III 5007, O I 6300, HAlpha, N II 6583, and S II 6717+6731, why do we need corresponding images from STIS? Firstly, there are some lines of crucial importance, such as N II 5755 for which no WFPC2 filters exist. Secondly, our aim is to form image ratios at the highest possible spatial resolution. Trying to overlay strips of PC images with corresponding STIS strip images is treacherous. The pixels sizes and orientations will differ. For complex images, regridding one image to match another involves inaccurate interpolations. (In IRAF trials, in which we rotated an image through angles A and -A, and then subtracted, the residuals reached 10 % for small objects.) Also, the PC images are contaminated (slightly but significantly) by continuum. For the program goals to be met we need sets of geometrically matched strip images. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8128( 4) - 03/30/00 11:46 - [ 3] Data Distribution Paper Products: NO Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8128( 4) - 03/30/00 11:46 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD220733- STAR, PLANETARY NEBULA RA=23H 25M 53.958S +/- 0.5", J2000 V = 13.3+/-0.1 OFFSET CENTRAL STAR DEC=42D 32' 5.28" +/- 0.5", E(B-V) = 0.11+/-0.03 PLATE-ID=02S2 TYPE=CONT Comments: THE COORDINATES OF THE STAR HAVE BEEN OBTAINED USING THE IRAF COMMAND "xy2ra" ON THE PC PATCH OF THE WFPC2 IMAGE u32e0408t.ecf.c0.fits 2 NGC7662-POS1 ISM, PLANETARY NEBULA, RA=23H 25M 53.666S +/- 0.5", J2000 F-LINE(6583)=1.8+/-0.5e-11 KNOT DEC=42D 31' 50.80" +/- 0.5", V = 16+/-1 PLATE-ID=02S2 Comments: THE COORDINATES OF POS1 HAVE BEEN OBTAINED USING THE IRAF COMMAND "xy2ra" ON THE PC PATCH OF THE WFPC2 IMAGE u32e0408t.ecf.c0.fits 3 NGC7662-POS2 ISM, PLANETARY NEBULA, RA=23H 25M 54.823S +/- 0.5", J2000 F-LINE(6583)=1.8+/-0.5e-11 KNOT DEC=42D 32' 13.12" +/- 0.5", V = 16+/-1 PLATE-ID=02S2 Comments: THE COORDINATES OF POS2 HAVE BEEN OBTAINED USING THE IRAF COMMAND "xy2ra" ON THE PC PATCH OF THE WFPC2 IMAGE u32e0408t.ecf.c0.fits 8128( 4) - 03/30/00 11:46 - [ 5] Visit: 01 Visit Priority: Visit Requirements: ORIENT 57.38D TO 59.38D ORIENT 237.38D TO 239.38D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD220733-OF STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.4 S FSET CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 HD220733-OF STIS/C ACQ/PEA 52X0.1 MIRROR 1 1 S FSET CD K ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC7662-POS STIS/C ACCUM 52X0.1 G750M 6581 CR-SPLIT=3,GAIN=4 1 34 M EXPAND 1 CD ------------------------------------------------------------------------------------------------------------------------------------ 40 NGC7662-POS STIS/C ACCUM 52X0.5 G750M 6581 CR-SPLIT=4,BINAXIS1=2,BINAXIS2=4, 1 44 M EXPAND 1 CD GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ 50 NGC7662-POS STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=8,BINAXIS1=1,BINAXIS2=4, 1 90 M EXPAND 1 CD GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ 8128( 4) - 03/30/00 11:46 - [ 6] Visit: 02 Visit Priority: Visit Requirements: SAME ORIENT AS 01 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD220733-OF STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.4 S FSET CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC7662-POS STIS/C ACCUM 52X0.5 G750M 5734 CR-SPLIT=8,BINAXIS1=2,BINAXIS2=4, 1 80 M EXPAND 1 CD GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC7662-POS STIS/C ACCUM 52X0.5 G750M 5734 BINAXIS1=2,BINAXIS2=4,CR-SPLIT=8, 1 90 M EXPAND 1 CD GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ 8128( 4) - 03/30/00 11:46 - [ 7] Visit: 03 Visit Priority: Visit Requirements: ORIENT 95.334D TO 97.334D ORIENT 275.334D TO 277.334D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD220733-OF STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.4 S FSET CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 HD220733-OF STIS/C ACQ/PEA 52X0.1 MIRROR 1 1 S FSET CD K ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC7662-POS STIS/C ACCUM 52X0.1 G750M 6581 CR-SPLIT=3,GAIN=4 1 34 M EXPAND 2 CD ------------------------------------------------------------------------------------------------------------------------------------ 40 NGC7662-POS STIS/C ACCUM 52X0.5 G750M 6581 BINAXIS1=2,BINAXIS2=4,CR-SPLIT=4, 1 44 M EXPAND 2 CD GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ 50 NGC7662-POS STIS/C ACCUM 52X0.5 G430L 4300 BINAXIS1=1,BINAXIS2=4,CR-SPLIT=8, 1 90 M EXPAND 2 CD GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ 8128( 4) - 03/30/00 11:46 - [ 8] Visit: 04 Visit Priority: Visit Requirements: SAME ORIENT AS 03 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD220733-OF STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.4 S FSET CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC7662-POS STIS/C ACCUM 52X0.5 G750M 5734 BINAXIS1=2,BINAXIS2=4,CR-SPLIT=8, 1 80 M EXPAND 2 CD GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC7662-POS STIS/C ACCUM 52X0.5 G750M 5734 BINAXIS1=2,BINAXIS2=4,CR-SPLIT=8, 1 90 M EXPAND 2 CD GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ 8128( 4) - 03/30/00 11:46 - [ 9] Summary Form for Proposal 8128 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.1 52X0.5 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT GAIN=4 BINAXIS2=4 BINAXIS1=1 BINAXIS1=2 CR-SPLIT=8 CR-SPLIT=3 CR-SPLIT=4 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 57.38D TO 59.38D ORIENT 237.38D TO 239.38D EXPAND SAME ORIENT AS 01 ORIENT 95.334D TO 97.334D ORIENT 275.334D TO 277.334D SAME ORIENT AS 03 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G750M G430L ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD220733-OFFSET NGC7662-POS1 NGC7662-POS2 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 6581 4300 5734 ------------------------------------------------------------------------------------------------------------------------------------